The present invention relates to devices for adjusting the spaced relationship between first and second members.
In the adjustment of optical elements in optical systems, critical alignment of the various optic elements is a factor which must be considered in making the adjustments. To accomplish this alignment, sensitive adjustment devices are used for orienting and displacing one or more of the optic elements in the system. This may be accomplished by mounting one or more of the elements on a plurality of adjustable legs such that adjustment of any one of the legs results in a corresponding orientation adjustment.
However, the problem with such adjustment devices is that they are usually accomplished by means of threaded screws. As is well known, threaded screws accomplish displacements in only one direction, that is, by a translation motion. It is apparent that while a linear motion is transmitted to the device being adjusted, the fixed relationship of the other mounting points on the device pivots the device during adjustment causing a lateral displacement of the device during the adjustment process. Therefore, in critical alignment arrangements such as are present in spacecraft apparatus wherein various sensors, motors and the like are aligned to a single axis, shims are utilized to provide the proper adjustment of the different apparatus involved. This is cumbersome and difficult, especially in a spacecraft where access to the adjustment devices may be hampered when the device to be adjusted is disposed in an enclosed structure. The adjustment devices, when of the screw-type, may also cause undesirable lateral stresses in the item being adjusted due to the lateral displacement. Such stresses cannot be tolerated in a spacecraft environment due to the extreme launch stresses since they may cause shifting of the optical alignment of the various adjusted apparatus during launch, causing failure of the mission.